if planning to do Deco, I plan with tables, pen/paper and math.
Then I cut my own backup tables.
Then I just use my computer for the tasks I need it for.
If I am following tables only with a set plan, I leave it in computer mode and just follow the running time.
I still pay attention to NDL and all too, sometimes I find that my profile doesn't even get me into deco, or it just barely tips me over the limit and I only need a few mins of deco, vs the much longer period of time I had scheduled on my hand calculated square profile. It's a bit harder to plan depths in a cave... so a square profile is not always optimal for caves with lots of lateral swimming and various depth changes.
Now, even if my computer calls for less deco, I'll still follow my hand cut tables up until the computer clears me.
I have VPlannner installed on my PCs, but tend to use iDeco Pro more often on my iphone/ipad since it's easier to deal with at a dive site.
I did make sure to change vplanner/ideco/computer all to as closely matching settings as I can, so I can use any for planning and it should be close enough.